If you have the sump room ? they are good for gas exchange and do give you a bit more room for error. I ran them for yrs and would still if room for the tower was not an issue we run them on the tanks where we grow out coral for sale systems are large and the gas exchange is better. I never in over 25yr plus have ever had a NO3's issue with their usage in any system I had them on. But you don't have to run them though.. _________ Some of the world's greatest feats were accomplished by people not smart enough to know they were impossible (Doug Larson) |